The present invention relates to an auto-focus lens module, especially to a lens module that uses electromagnetic force as well as spring compression force as driving force.
Either digital cameras or mobile phones with shooting function are disposed with a lens module that includes a focus adjusting device. The lens module available now has features of light weight, compact size, precision and durability. For example, it is guaranteed that the focus adjusting device should be operated at least two hundred thousand times without loosing. In conventional focus adjusting devices, electromagnetic force is used and the coils are surrounding a lens holder composed by a lens and a sleeve. A magnet arranged outside the coils is a circular magnet. Thus the volume occupied by the lens module is quite large, against the principle of compact design. Moreover, spring blades are used to balance the electromagnetic force. However, the spring blades are easy to be deformed by external forces such as vibration, rebounding or after being used for a long time so that the stability and accuracy of the movement of the lens holder have been affected.